This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 58 |
| 4 | 501 |
| 5 | 5402 |
| 6 | 69909 |
| 7 | 1055458 |
| 8 | 18211401 |
| 9 | 353506802 |
| 10 | 7624471809 |
| 11 | 180889942858 |
| 12 | 4681743794301 |
| 13 | 131269240120202 |
| 14 | 3963720131525709 |
| 15 | 128234893954822258 |
| 16 | 4425253713052509201 |
| 17 | 162255367355408805602 |
| 18 | 6299173242134303391609 |
| 19 | 258136328705500135053658 |